Hyaluronic acid (HA) is naturally present in the highest concentrations in fluids in the eyes and joints. The hyaluronic acid for medicine is either extracted from rooster combs or biologically synthesized in bacteria. Hyaluronic acid is a glycosaminoglycan that helps in transportation of nutrients through the body and facilitate water retention in body tissue. It is naturally found in body; in joints, eye cavity, and immune system. Hyaluronic acid is used for various joint disorders, including osteoarthritis and during certain eye surgeries including cataract removal, corneal transplantation, and repair of a detached retina and other eye injuries. It is injected into the eye during the procedure to help replace natural fluids. It can be taken by mouth or injected into the affected joint.